1. Field of the Invention
The present invention relates to a method of fabricating an electron source substrate by subjecting electroconductive members to an energization forming operation to provide the electroconductive members with an electron-emitting function, to a method of fabricating an image forming apparatus by utilizing the electron source substrate fabricating method, to a system for fabricating an electron source substrate, and to an energization forming method for electroconductive members.
2. Related Background Art
Electron-emitting devices are roughly classified into two types, thermal electron-emitting devices and cold cathode electron-emitting devices. As cold cathode electron-emitting devices, there are metal/insulator/metal electron-emitting devices, surface conduction electron-emitting devices and the like.
A surface conduction electron-emitting device utilizes the phenomenon that electrons are emitted by flowing current through a small area of a thin film formed on a substrate, along a direction in parallel to the film surface.
The assignee of the present invention has submitted various proposals of a surface conduction electron-emitting device having a novel structure and its applications. The fundamental structure and fabricating method are disclosed, for example, in Japanese Patent Application Nos. 7-235255, 8-171849 and the like.
A surface conduction electron-emitting device has an electroconductive film with a partial, electron-emitting region connected to a pair of opposing device electrodes formed on a substrate. A fissure is formed in the partial electron-emitting region of the electroconductive film. Deposition films having as their main composition at least one of carbon and carbon compound at both ends of the fissure.
A plurality of such electron-emitting devices are disposed on a substrate and wired so that an electron source substrate having a plurality of surface conduction electron-emitting devices can be fabricated.
By combining the electron source substrate and a phosphor substrate, a display panel of an image forming apparatus can be fabricated.
Conventionally, such an electron source substrate has been fabricated as in the following manners.
According to a first fabricating method, first, an electron source substrate is formed which has a plurality of devices each having an electroconductive film and a pair of device electrodes connected to the electroconductive film, respectively formed on the substrate, the devices being wired together. Next, the formed electron source substrate is placed in a vacuum chamber. After the inside of the vacuum chamber is evacuated, voltage is applied to each device via an external terminal to form a fissure in the electroconductive film of each device (forming a fissure in the electroconductive film of each device is hereinafter called a forming operation). Gas which contains organic material is introduced into the vacuum chamber and voltage is again applied to each device via the external terminal under the atmosphere which contains organic material to thereby depositing carbon or carbon compound near the fissure (depositing carbon or carbon compound near the fissure is hereinafter called an activation operation).
According to the second fabricating method, first, an electron source substrate is formed which has a plurality of devices each having an electroconductive film and a pair of device electrodes connected to the electroconductive film, respectively formed on the substrate, the devices being wired together. Next, the formed electron source substrate is bonded to a phosphor substrate with a support frame being interposed therebetween to form a panel of an image display apparatus. After the inside of the panel is evacuated via an exhaust pipe, voltage is applied to each device via an external terminal to form a fissure in the electroconductive film of each device (a forming operation). Gas which contains organic material is introduced into the panel via the exhaust pipe, and voltage is again applied to each device via the external terminal under the atmosphere which contains organic material to thereby deposit carbon or carbon compound near the fissure (an activation operation).
Although the first and second fabricating methods have been used conventionally, the first fabricating method requires a larger vacuum chamber and an evacuation system of high vacuum particularly when the electron source substrate becomes large.
With the second fabricating method, the space in the panel of an image forming apparatus is very narrow (about several mm in the case of a panel using surface conduction electron-emitting devices). It takes a long time to introduce gas which contains organic material into the space of the panel and to drain the gas.